﻿//  Copyright 2016 Google Inc. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.

using NtApiDotNet;
using NtObjectManager.Utils;
using System.Management.Automation;

namespace NtObjectManager.Cmdlets.Object
{
    /// <summary>
    /// <para type="synopsis">Open an NT object by path.</para>
    /// <para type="description">This cmdlet opens an NT object by its path. The returned object
    /// will be a type specific to the actual underlying NT type.
    /// </para>
    /// </summary>
    /// <example>
    ///   <code>$obj = Get-NtObject \BaseNamedObjects\ABC</code>
    ///   <para>Get a existing object with an absolute path.</para>
    /// </example>
    /// <example>
    ///   <code>$obj = Get-NtObject \BaseNamedObjects -TypeName Directory</code>
    ///   <para>Get a existing object with an explicit type.</para>
    /// </example>
    /// <example>
    ///   <code>$root = Get-NtDirectory \BaseNamedObjects&#x0A;$obj = Get-NtObject ABC -Root $root</code>
    ///   <para>Get an existing object with a relative path.</para>
    /// </example>
    /// <para type="link">about_ManagingNtObjectLifetime</para>
    [Cmdlet(VerbsCommon.Get, "NtObject")]
    [OutputType(typeof(NtObject))]
    public sealed class GetNtObjectCmdlet : NtObjectBaseCmdletWithAccess<GenericAccessRights>
    {
        /// <summary>
        /// <para type="description">The type of object will try and be determined automatically, however in cases where this isn't possible the NT type name can be specified here.
        /// This needs to be a value such as Directory, SymbolicLink, Mutant etc.
        /// </para>
        /// </summary>
        [Parameter]
        public string TypeName { get; set; }

        /// <summary>
        /// <para type="description">The NT object manager path to the object to use.</para>
        /// </summary>
        [Parameter(Position = 0, Mandatory = true)]
        public override string Path { get; set; }

        /// <summary>
        /// Determine if the cmdlet can create objects.
        /// </summary>
        /// <returns>True if objects can be created.</returns>
        protected override bool CanCreateDirectories()
        {
            return false;
        }

        /// <summary>
        /// Get the base object manager path for the current powershell directory.
        /// </summary>
        /// <returns>The base path.</returns>
        protected override NtResult<string> GetBasePath()
        {
            var result = base.GetBasePath();
            if (result.IsSuccess)
                return result;
            return PSUtils.GetFileBasePath(SessionState);
        }

        /// <summary>
        /// Method to create an object from a set of object attributes.
        /// </summary>
        /// <param name="obj_attributes">The object attributes to create/open from.</param>
        /// <returns>The newly created object.</returns>
        protected override object CreateObject(ObjectAttributes obj_attributes)
        {
            string type_name = string.IsNullOrWhiteSpace(TypeName) ? NtDirectory.GetDirectoryEntryType(ResolvePath(), Root) : TypeName;
            return NtObject.OpenWithType(type_name, ResolvePath(), Root, AttributeFlags, Access, SecurityQualityOfService);
        }
    }
}
